This invention relates to a rail bed maintenance apparatus and, more particularly, to a vehicle with apparatus for removing and replacing railway cross ties from a rail bed.
In U.S. Pat. No. 4,418,625, assigned to the assigneee of this application, there is disclosed an apparatus which provides for efficient replacement of railway cross ties. In this apparatus, a vehicle designed to travel along the railway track is provided. A tie exchanging mechanism, mounted on the vehicle, comprises a pair of jaws on each side of the vehicle, adapted to grip the ends of the railway cross ties in the road bed and a hydraulic mechanism to move either pair of jaws laterally with respect to the rails. When a pair of jaws of the tie exchanging mechanism has gripped the end of a tie, the hydraulic mechanism can be operated to pull the cross tie from beneath the rails. After a tie has been removed from beneath the rail, a new tie may be substituted for the tie that has just been removed using the same tie exchanging mechanism, but in this instance, the mechanism will push the new tie into place. Because the tie gripping jaws are provided and can be operated on each side of the vehicle, a tie may be removed and replaced from either side of the rail bed.
The machine, described above, has proved to provide an efficient technique of replacing railway cross ties. However, in some instances, when a tie is being replaced, the track rails will flex out of proper alignment, particularly in hot weather. When this happens, it is difficult to get the flexed rail back into proper alignment and it sometimes becomes necessary to replace the flexed portion of the rail by cutting out the flexed section and rewelding a new section in place.